Field of the Invention
The present disclosure is directed to a brake mechanism for a railway vehicle, and, further, to a device for correcting uneven brake shoe wear on the brakes of a railway vehicle.
Description of Related Art
Various brake mechanisms for railway vehicles are known in the art. In a truck-mounted brake mechanism, such as the TMX® or UBX® systems, owned by WABTEC Holding Corp., the Assignee of the present invention, two brake beams are provided per truck to provide the braking force to the two axles of the truck. The two brake beams are activated by at least one brake cylinder that is in fluid communication with a source of compressed air, such as an air reservoir mounted on the body of the railway vehicle.
In general, each brake beam includes a compression beam having its terminal ends coupled to the ends of a V-shaped tension beam. A brake head is provided at the opposing terminal ends of the compression beam and/or the V-shaped tension beam. Each brake head includes a brake shoe carrier adapted to receive a removable brake shoe. The brake mechanism is coupled to the truck of the railway vehicle at end portions of the brake heads. In operation, the brake beam having the compression beam and the V-shaped tension beam is suspended and contained within the railway truck bogie to allow movements with the truck.
During the braking operation, a non-uniform wear of the consumable material of the brake shoes may occur as the components of the brake mechanism wear toward their condemning limits. In such a scenario, the brake beams tend to rotate relative to side frames and the wheels, which forces an upper end of the brake shoes closer to the wheel relative to the lower end of the brake shoes. Such uneven contact of the brake shoes increases the wear rate of the upper end of the brake shoes relative to the lower end of the brake shoes. In certain situations, the uneven wear leaves the shoe material at the upper end of the brake shoe at the condemnable limit, while the shoe material at the lower end of the brake shoe is still serviceable. In extreme cases, the material of the brake shoe at the upper end may become so worn as to cause the metal backing plate of the brake shoe to be exposed and contact the wheel, thereby causing damage to the brake head, the backing plate, and the wheel. Another common problem is that, as the components of the brake mechanism gradually wear out, the compression beam may come into contact with a slack adjuster. During operation, continued contact between the compression beam and the slack adjuster may cause wear on the compression beam and/or the slack adjuster.